So we've had a fair few reports of fbcon handover breakage betweenefi/vesafb and i915 surface recently, so I dedicated a couple ofdays to finding the problem.

Essentially the last thing we saw was the conflicting framebuffermessage and that was all.

So after much tracing with direct netconsole writes (printksunder console_lock not so useful), I think I found the race.

Thread A (driver load) Thread B (timer thread) unbind_con_driver -> | bind_con_driver -> | vc->vc_sw->con_deinit -> | fbcon_deinit -> | console_lock() | | | | fbcon_flashcursor timer fires | console_lock() <- blocked for A | |fbcon_del_cursor_timer -> del_timer_sync (BOOM)Of course because all of this is under the console lock,we never see anything, also since we also just unbound the activeconsole guess what we never see anything.

Hopefully this fixes the problem for anyone seeing vesafb->kmsdriver handoff.